Diagnosing MS can be challenging because its symptoms are similar to those of other nervous system diseases. In addition, no specific marker for MS has been identified. That means diagnosis is based on the combination of a physical exam, a person’s medical history and symptoms, and a variety of tests.
Tests to diagnose MS may include blood tests and a spinal tap. These tests allow doctors to rule out other conditions, such as a viral infection or other inflammatory diseases. Magnetic resonance imaging, or MRI, also is needed in helping to identify MS.
MRI can show lesions that appear to be due to myelin loss. However, these types of lesions also can be caused by other conditions, such as lupus, migraine headaches and diabetes. So the presence of these lesions alone cannot be considered definitive proof of multiple sclerosis.
Another test used to diagnose MS measures the electrical signals sent by the brain in response to a stimulus. This test, called an evoked potential test, can help detect lesions or nerve damage in the optic nerve, brainstem or spinal cord even when there are no obvious symptoms of nerve damage.
MS behaves somewhat differently in every person. That makes it very important for the spectrum of tests used to diagnose MS to be tailored to an individual’s situation.
The results also need to be carefully considered along with findings from a physical exam and information gathered in the medical history.
In most cases, it is only with this type of thorough evaluation that a health care team can confidently arrive at a diagnosis of MS. -- Orhun Kantarci, M.D., Neurology, Mayo Clinic, Rochester, Minn.
Medical Edge from Mayo Clinic is an educational resource and doesn’t replace regular medical care. E-mail a question to email@example.com. For more information, visit www.mayoclinic.org.